The Soils of Elgin County - Agriculture and Agri-Food Canada

Soil ClassificationSoil TaxonomyThe Canadian System of Soil Classification(11), classifies soils taxonomically according to thetype, degree of development, and sequence of soilhorizons present in the soil profile . The highesttaxonomic category is the order . Based ondifferences in soil development and horizonation,each order is subdivided into great groups ; greatgroups into subgroups; subgroups into families;and families into series . Soil series may be furthersubdivided into phases on the basis of physical orchemical features which are present. The soilsdescribed in his report are either soil series orphases of soil series. In the legend provided oneach soil map, soil series and phases of soil serieshave been grouped under the heading "soil types" .Soil orders that have been noted in ElginCounty are the Luvisolic, Brunisolic, Gleysolic,Regosolic and Organic orders . Most well andimperfectly drained soils in the County have beenclassified in the Luvisolic order. They arecharacterized by light coloured eluvial horizonsand darker coloured illuvial B horizons in whichclay has accumulated. Poorly drained soils in theCounty were usually classified in the Gleysolicorder.In this report the taxonomic classifications ofthe soils have been determined at the subgrouplevel . Examples of some subgroup classificationsfor well drained soils which occur in the Countyare Gray Brown Luvisol and Brunisofic GrayBrown Luvisol . Some examples for imperfectlydrained soils are Gleyed Gray Brown Luvisol andGleyed Melanic Brunisol. Poorly drained soilswere usually classified as Orthic Humic Gleysols.Soil SeriesThe soil series recognizes relatively detailedsoil properties related to soil development andhorizonation . Examples of some properties whichare important when defining a soil series includesoil texture, drainage, colour, and thickness ofhorizon .Standard classification guidelines (11,12,13)were applied to define the soil series described inthis report . According to those guidelines, thedetermination of soil drainage was based on anexamination of soil colours using Munsell SoilColour Charts (15) .Soil materials which are saturated for shortperiods, primarily in the spring, develop orange orrust coloured "mottles" which are primarilycausedby the oxidation of iron compounds in the soil.Soil materials which are subject to more prolongedperiods of saturation exhibit "gley" conditions.This condition is expressed as bluish-gray or graysoil colours, and are mainly caused by thereduction of iron compounds in the soil.When the depth at which these colours occurin the profile is determined, it is possible toestimate the depth at which the water table occursand for what portion of the year it is present.Examples of some typical soil profiles andassociated soil colours are depicted in Figure 10 .Forty-four soil series were identified during theresurvey of the County and are described on thesoil maps and in the report. An example is theMuriel soil (MU), which is a moderately welldrained, clayey textured glacial till soil .Soil PhasesPhases were applied to soil series whendifferences were present in soil properties whichwere considered significant for plant growth orsoil management . For example, the TO.L mapsymbol represents a Toledo loamy phase soil. Itdiffers from a Toledo soil by having 15 to 40 cm ofloamy material overlying clayey lacustrinematerial. Thirty-three phases of soil series wereidentified. Descriptions of the phases which wereapplied to soils mapped in the County are asfollows :C - 15 to 40 cm of sandy textured material overmaterials with contrasting texturesF - 15 to 40 cm of clayey textured material overmaterials with contrasting texturesL - 15 to 40 cm of loamy textured material overmaterial with contrasting texturesP - 15 to 40 cm of organic (peaty) material overmineral soil materialT - 40 to 100 cm of lacustrine sediments overclayey textured till materialW - 40 to 100 cm of loamy textured, lacustrinemodified glacial till material over clayeytextured glacial till materialSoil Profiles and HorizonsA soil profile is a vertical section of the soilthrough all its horizons and extending into theparent material (16). A soil horizon is "a layer ofmineral or organic soil or soil materialapproximately parallel to the land surface that hascharacteristics altered by processes of soilformation. It differs from adjacent horizons inproperties such as colour, structure, texture andconsistence, and in chemical, biological, andmineralogical composition" (11) . Some examples18